Motive power of vehicles has been diversified, and various technologies are installed depending on the motive power of a vehicle. For example, there has been a technology that has the engine of a vehicle stop automatically when the vehicle makes a temporary stop or the like, and has the engine restart automatically when the vehicle restarts (see, for example, Patent Document 1). Such a technology has been known as “idling stop”. A vehicle in a state where the engine has stopped by idling stop, starts when a restart condition is satisfied, which is different from a case where the engine has stopped by a driver's operation. Also, vehicles that can stop engines while traveling (the vehicle speed is greater than zero) have come onto the market. Since such a vehicle can maintain normal vehicle performance while stopping the engine, stoppage of the engine does not necessarily mean stoppage of the motive power, and hence, it is difficult for a driver to determine whether the motive power stops. Also, in the first place, since silencing of engine sound has been improved, sound and vibration of engines have become less sensible.
Also, a hybrid vehicle has an EV mode in which the vehicle can travel normally even when the engine stops, and stoppage of the engine while traveling is not a rare phenomenon nowadays. Note that, in a hybrid vehicle, operation or stoppage of the motive power (at least one of the engine or the motor) can be recognized on a READY indicator in a meter panel (displayed when a relay turns on that is provided to supply a high voltage to the motive power source). As for an electric vehicle, it does not have an engine built in from the outset. Therefore, it can be considered as the same as a hybrid vehicle having the engine always stopped.
Also, an increasing number of vehicles now provide simple activation and stopping operations of the motive power implemented with push buttons or the like. As such an operation is simpler than rotating a mechanical key, there is a likelihood that a driver is not surely conscious that the operation the driver is doing is a stoppage operation. For example, one may be concerned about there is a likelihood that a driver mistakenly operates a push button that is not for activation or stoppage of the engine, or unintentionally stops the motive power.
A technology has been proposed that suppresses inconvenience generated if an engine starts while the engine is stopped, and the driver is not conscious of it (see, for example, Patent Document 2). Patent Document 2 discloses a control apparatus for stopping and starting an engine for an idling-stop vehicle. If the apparatus determines that there is a likelihood that the engine will go out of control when starting it, the apparatus indicates information about the engine that is not to be started, and information to prompt the driver to take necessary operations for starting the engine.
However, Patent Document 1 has a problem in that measures are not described that need to be taken when the motive power stops while traveling.
In a vehicle having an engine built in, the engine generates oil pressure and/or negative pressure, to be used for assisting power steering and assisting brake operations. Therefore, if the engine stops, vehicle functions are reduced into a state where the driver does not intend to be. Also, in a hybrid vehicle or an electric vehicle, the vehicle performance is reduced when it is transitioned out of a READY-ON state. Therefore, in a state where the motive power stops while traveling, it is preferable to promptly indicate the state to the driver to take appropriate measures.
[Patent Document 1] Japanese Laid-open Patent Publication No. 2009-2236
[Patent Document 2] Japanese Laid-open Patent Publication No. 2000-234538